A well-ordered set is a type of mathematical set that is equipped with a specific ordering relation. In a well-ordered set, every non-empty subset has a least element, meaning there is always a smallest member in any group of elements. This property ensures that you can always find a starting point when examining the set. An example of a well-ordered set is the set of natural numbers, 0, 1, 2, 3, .... In this set, any subset, such as 2, 3, 5, has a least element, which is 2 in this case. This concept is important in various areas of mathematics, including set theory and ordinal numbers.